Tube drawing machine



Jan. 19, 1960 .1. I. MCMARTIN TUBE DRAWING MACHINE 3 Sheets-Sheet 1Filed Aug. 15, 1957 FIG.

AT oR/VEYS Jan. 19, 1960 J. 1. MCMARTIN TUBE DRAWING MACHINE 5Sheets-Sheet 2 Filed Aug. 15, 1957 FIG. 2

INVENTOR. (/A MES Z MOMART/N ATTORNEYS Jan. 19, 1960 J. I. MCMARTIN TUBEDRAWING MACHINE 3 Sheets-Sheet 3 Filed Aug.. 15, 1957 @A N@ NW Wm WMUnited TUBE DRAWING MACHINE James I. McMartin, -West Hartford, Conn,assignor to The Fenn Manufacturing Company, Newington, Conn., acorporation of Connecticut Application August 15, 1957, Serial No.678,309

-7 Claims. (Cl. 205-3) type to provide axial displacement or traverse ofthe swift relative'to the block during the reducing operation in orderto coil the tubing in a helix upon the block.

It is the object of this invention to provide a tube drawing machine ofthe type described having a novel and improved traverse control toregulate the rateof relative axial displacement of the block and swiftduring a drawingoperation in direct relation to the speed of rotation ofthe block.

Other objects will be in part obvious, and in part pointed out more indetail hereinafter.

"The invention accordingly consists in the features of construction,combination of 7 elements v and arrangement of parts which will beexemplified in the construction hereafter set forth and the scope of theapplication of which will be indicated in the appended claims.

'In the drawings:

Fig. 1 is a front elevational View of a tube drawing machine of a typewith which this invention is concerned;

Fig. 2 is a fragmentary cross sectional view substantially along theline 22 of Fig. 1; and

Fig. 3 is a diagrammatic view of an electro-hydraulic traverse control,for the machine ofFig. 1, constructed in accordance with the invention.

With reference to the drawings, and particularly Figs.

' l and2, a drawing machine of a type suitable for drawing wire, tubingand the like, with which this invention is concerned, comprises a frameon which is rotatably supported a vertically disposed block 12. Theblock is driven by an electric motor 14 through suitable reductiongearing l. A swift 18 is supported on a base 26 slidably mounted on theframe as at 22 for vertical movement of the swift relative to the block12 in a direction parallel to the rotationalaxis of the block. Drawingdies24 are carried by the swift and a clamping fixture 26 is mounted onthe block 12 for engagement \m'th one end of tubing carried by the swiftto draw the tubing through the dies in response to rotation of theblock.

A hydraulic cylinder 28 is supported in a vertical position on the frame1% A piston rod 30 of a piston (not shown) in the cylinder 28 isconnected to the swift base 20' for vertical movement therewith.Positive stops (not shown) are provided to limit vertical movement ofthe swift in either direction. As will be hereinafter explained indetail, means are provided to introduce hydraulic fluid beneath thepiston in the cylinder 28 to raise the swift andsubsequently to bleedthe hydraulic "fluid from beneath the piston in direct relation to theend to the valve 92 for drainage.

ZfiZLWl Fatente cl Jan. 19, 1960 the invention, the hydraulic portion ofthe system comprises a constantdelivery hydraulic pump 36 driven by anelectric motor 38. The intake of the pump 36 is connected by a conduit39 to a tank 40 containing a supply of hydraulic fluid. The exhaust ofthe pump 36 is connected to a conduit 42 having a branch passageconnected to a relief valve 44 and a pressure gage 46. The valve 44 ismanually adjusted and is connected through a conduit 45 back to the tank40.

The conduit 42 is connected to a port 50 of a four-way valve 52 havingadditional ports 54, 56 and 58 as well as a drain port 60. The'valve 52is shiftable in one direction by a solenoid S1 to form a fluidconnectionbetween the ports 50 and 54 and also between the ports 56 and58, as shown in solid lines, in response to energizing of the solenoid Asolenoid S3 is operable to shift the valve in the opposite direction toconnect the ports 54 and 58 and the ports 56 and 50, as shown in dottedlines The ports 56 and 58 are connected by conduits 57 and'59respectively to a conduit 74 leading to the supply tank 40. The port 54is connected by aconduit 62, through a one-way valve 64, to a second oneway valve 66 and a metering orifice 6s disposed in parallel relation.The one-way valve 66 and metering orifice 68 are connected by a conduit70 to the bottom of the cylinder- 28. A conduit 72 is connected at oneend ment in one direction, the ports 78 and 82 will be connected, asshown in dotted lines, and upon movement in the other direction, theports 78 and 84 will be connected, as shown in solid lines. A solenoidS2 is operable to j shift the valve in said one direction to connect theports '78 and 82 and a return spring (not shown) is provided to shiftthe valve in said other direction to 'connect the ports 78 and 84. Theport 82 is connected by means of a conduit to a manually operable flowcontrol valve 92 connected to the conduit 74 leading to the supply tank40. A conduit 94 is connected at one The conduit 94 is connected at itsother end to a conduit 96 leading to the supply tank 40 and alsoconnected to the drainage ports 60 and 38 of the valves 52 and 80,respectively.

In accordance with the invention, a pump 98,.such as a gear pump,havinga capacity directly proportional to the speed of operationthereof, is connected at its inlet through a conduit to the conduit 62on the down stream side of the one-way valve ,64 so that on operation ofthe pump 98, fluid will be drawn from the bottom of the cylinder 28through the metering orifice 68. The pump 98 is drivingly connected to avariable speed direct current motor 99 for operation thereof.Theoutletof the pump 98 is connected by a conduit 102 through anadjustable relief valve 1114 and to the conduit 62 on the up stream sideof the one way valve 64.

pump 36 is connected to a source of power through lines 106, 108 and 110and a suitable motor control (not shown). A transformer 112 has itsprimary connected to the lines 106 and 108. A line 114 leads from oneside of the secondary of the transformer 112 to a line 116 which isconnected to one side of the solenoid S3. The other side of the solenoidS3 is connected by a line 118 to one side of a single pole, singlethrow, normally open limit switch L2. The limit switch L2 is positionedrelative to the swift for actuation thereby to close the switch as theswift reaches its upper limit of travel. The other side of the limitswitch L2 is connected by a line 120 to one side of a single pole,single throw, normally open limit switch L1 and line 120 is alsoconnected to a line 122 leading to the other side of the secondary ofthe transformer 112. The limit switch L1 is positioned relative to theswift for momentary actuation thereby to close the switch during upwardmovement only of the swift and preferably just prior to actuation of thelimit switch L2. The other side of the limit switch L1 is connected by aline 124 to one side of the solenoid S2. The other side of the solenoidS2 is connected to line 114 leading to the transformer 112. The line 124is connected by a line 126 and a line 140 through an associated pair ofpoles of a double pole, single throw, normally closed limit switch L3.The limit switch L3 is positioned relative to the swift for actuationthereby to open the switch as theswift moves into its lower limit oftravel.

The solenoid S1 is connected at one side by a line 130 to the line 114.The other side of the solenoid S1 is connected by line 132 and anormally open switch 134 to line 122 which is also connected to one sideof a normally open switch 138. The other side of the switch 138 isconnected to line 140 leading to the limit switch L3. The remaining pairof poles of the limit switch L3 is connected between line 120 connectedto the power line 122 and a line 142 leading to one side of a normallyclosed switch 146, the other side of which is connected to an emergencystop control 148 on the block motor 14. The other side of the stopcontrol 148 is connected through line 150 to line 114 leading to thetransformer 112. The control 148 is adapted to de-energize the motor 14in response to disconnection of the control from the power line 122.

In accordance with the invention, the armature of the motor 99 for thepump 98 is connected by lines 152 and 154 to an electronic variablespeed motor control 156 connected to a tachometer generator 158 for itssource of power. The tachometer generator 158 is drivingly connected tothe block motor 14. A potentiometer 162 connected to the variable speedmotor control 156 permits adjustment by the operator of the ratio of thespeed of the direct current motor 99 to the speed of the block motor 14for any given speed of the block motor.

During the operation of the tube drawing machine incorporating a swifttraverse control constructed in accordance with the invention, when itis desired to raise the swift from the down position, preparatory to adrawing operation, the motor 38 being energized, the switch 134 isclosed to energize the solenoid S1 and connect the ports 50, 54, 56 and58 of the valve 52 as shown in solid lines. Hydraulic fluid will thusflow from the tank 40 through the pump 36, conduit 42, ports 50 and 54of the valve 52, conduit 62, and one-way valve 64 and through theone-way valve 66 and metering orifice 68 to conduit 70 connected to thebottom of the cylinder 28 beneath the piston therein. During raising ofthe swift, the fluid displaced from the top of the cylinder 28 will flowthrough conduit 72 to conduit 74 and into the tank 40. Upon suflicientraising of the swift, and as heretofore mentioned preferably just priorto the swift reaching its upper limit of travel, the limit switch L1will be momentarily closed so as to energize the solenoid S2 to shiftthe valve 80 and connect the ports 78 and 82. Hydrulic fluid will thusbe bled from the line 62, through the line 76, valve 80 and line 90, andthrough the flow control valve 92 back into the tank 40. The rate atwhich fluid is bled from the line 62 is controlled by the setting of theadjustable flow control valve 92 and should be selected to be suflicientto substantially reduce the rate of upward movement of the swift inorder to cushion its engagement with the upper limit stops.

As the swift reaches its upper limit of travel, the limit switch L2 willbe closed to energize the solenoid S3 and shift the valve 52 to connectthe ports 54 and 58 and ports 50 and 56 thereof, as shown in dottedlines. Fluid from pump 36 will, thus, now be directed through ports 50and 56 to conduit 74 leading to tank 40. The oneway valve 64 willprevent back flow from the underside of the cylinder 28 through theconduit 62 to the port 54 of the valve 52. The relief valve 104 inconduit 102 is adjusted relative to the weight of the piston in thecylinder 28 and the components movable therewith to prevent fluid flowfrom the underside of the cylinder 28 through the conduit 102 unless thepump 98 is being driven by the motor 99. Thus, the swift is nowmaintained in its upper limit of travel.

The tubing carried by the swift may now be threaded through the dies andclamped on the block 12. By a suitable motor control (not shown) theblock motor 14 is then energized, which, through the tachometergenerator 158 and motor control 156, results in energizing of thearmature of the motor 99 to elfect operation of the constantdisplacement pump 98. The pump 98 will draw hydraulic fluid from theunderside of the cylinder 28 through the passage 70, metering orifice68, and passage 100 and exhaust fluid through line 102, relief valve104, conduit 62, and ports 54 and 58 of the valve 52 to the tank 40. Thesize of the metering orifice 68 is preferably sufficiently large so asnot to interfere with the normal control of the rate of descent of theswift as effected by the pump 98. It is, however, preferablysufficiently small so that if a failure occurs in the system, it willprevent the swift from falling freely.

During the descent of the piston under the control of the pump 98, itis, of course, desired that the ratio of the rate of descent of thepiston relative to the rotative speed of the block be lower for a givenblock speed when relatively small diameter tubing is to be drawn, thanwhen relatively large diameter tubing is to be drawn. The potentiometer162 provides the machine operator with a means for initially adjustingthe rate of traverse of the swift relative to block speed for anyparticular size tubing. When the swift reaches its lower limit oftravel, limit switch L3 will be actuated to open the connection betweenlines and 142 to actuate the block motor control 148 and de-energize theblock motor. De-energizing of the block motor will, of course, result inthe de-energizing of the armature of the pump motor 99 to halt operationof the pump 98.

If it is desired to lower the swift from the raised positionindependently of the pump 98, the normally open switch 138 is closed toconnect the power line 122 to'line 126 connected to line 124 leading tothe solenoid S2 to actuate the solenoid and shift the valve 80 andconnect the ports 78 and 82 thereof. The underside of the cylinder 28will thus be connected to conduit 90 and through the metering valve 92to the tank 40, whereupon, the swift willdescend under the control ofthe valve 92.

A tube drawing machine of the type described and incorporating theelectro-hydraulic control system described will provide coiling of thedrawn tubing on the block in a tight helix regardless of the size of thetubing or the speed of block rotation. The use of a constantdisplacement hydraulic pump driven by a variable speed electric motorresponsive to the speed of rotation of the block provides a verysensitive and accurate, yet easily adjusted traverse control. Theelectro-hydraulic control system of the invention will provide long andtrouble free service with a minimum of maintenance, thus assuring theapplicability of the machine to mass production operation.

I claim:

1. In a tube drawing machine, a frame, a block rotatably supported onthe frame, a motor drivingly connected to said block, a swift supportedon the frame for movement relative to the block in a direction parallelto the rotational axis of the block, a hydraulic cylinder supported onthe frame, a piston in said cylinder connected to the swift for movementtherewith, and means for controlling the rate of movement of the pistonrelative to the block comprising a hydraulic pump having a capacitydirectly related to the speed of operation thereof connected to saidcylinder on one side of said piston, and electrical means responsive tothe speed of rotation of the block drivingly connected to the pump.

2. In a tube drawing machine, a frame, a block rotatably supported onthe frame, a motor on the frame drivingly connected to the block, aswift supported on the frame for movement relative to the block in adirection parallel to the block rotational axis, a hydraulic cylinder onthe frame, a piston in said cylinder connected to said swift formovement therewith, and means for controlling the rate of movement ofthe piston comprising a hydraulic pump with a capacity directly relatedto the speed of operation thereof connected to said hydraulic cylinderon one side of said piston, a variable speed electric motor drivinglyconnected to the pump, and electrical control means for energizing thevariable speed motor in response to the rate of rotation of the block.

3. In a tube drawing machine, a frame, a block supported on the framefor rotation, a motor on the frame drivingly connected to the block, aswift supported on the frame for movement relative to the block in adirection parallel to the block rotational axis, a hydraulic cylinder onthe frame, a piston in said cylinder connected to said swift formovement therewith, and means for controlling the rate of movement ofsaid piston comprising a hydraulic pump with a capacity directly relatedto the speed of operation thereof connected to said hydraulic cylinderat one side of said piston, a variable speed electric motor drivinglyconnected to the pump, a generator connected to the block motor foroperation thereby, and electrical control means connected between saidgenerator and variable speed motor to vary the speed of said variablespeed motor in response to the output of said generator.

4. In a tube drawing machine, a frame, a block rotatably supported onthe frame, a motor on the frame drivingly connected to the block, aswift supported on the frame for movement relative to the block, ahydraulic cylinder on the frame, a piston in said cylinder connected tosaid swift for movement therewith, and means for controlling the rate ofmovement of said piston comprising a constant displacement pump having acapacity directly related to the speed of operation thereof connected tosaid cylinder on one side of .said piston, a variable speed electricmotor drivingly connected to said pump, a generator connected to theblock motor for operation thereby, and electrical control meansconnected between said generator and variable speed motor for varyingthe speed of the variable speed motor in response to output of thegenerator and including manually operable proportioning means foradjusting the ratio of the speed of the variable speed motor to thespeed of the block motor.

5. In a tube drawing machine, a frame, a vertically disposed blockrotatably supported on the frame, a motor drivingly connected to saidblock, a vertically disposed swift supported on the frame for verticalmovement relative to the block, a vertically disposed hydraulic cylindersupported on the frame, a piston in said cylinder connected to the swiftfor vertical movement therewith, a pump having a capacity directlyproportional to the speed of operation thereof, means connecting theinlet of said pump to said cylinder beneath said piston, a relief valvein series with the outlet of said pump, a variable speed electric motordrivingly connected to said pump, and electrical control meansresponsive to operation of the block motor connected to said electricmotor to regulate the speed thereof in direct relation to the speed ofrotation of the block.

6. In a tube drawing machine, a frame, a vertically disposed blockrotatably supported on the frame, a motor drivingly connected to saidblock for rotation thereof, a vertically disposed swift supported on theframe for limited vertical movement relative to the block, a verticallydisposed hydraulic cylinder supported on the frame, a piston in saidcylinder connected to the swift for vertical movement therewith, asource of hydraulic fluid under pressure, means to connect said sourceof fluid to said cylinder beneath said piston to raise said swiftincluding means to disconnect said source from said cylinder in responseto movement of said swift into its upper limit of travel, a pump havinga capacity directly proportional to the speed of operation thereofconnected to said cylinder to draw fluid from beneath said piston, anadjustable relief valve in series with the outlet of said pump, andelectrical means responsive to operation of the block motor to operatesaid pump at a speed directly related to the speed of rotation of saidblock.

7. In a tube drawing machine, a frame, a vertically disposed blockrotatably supported on the frame, a motor drivingly connected to saidblock, a vertically disposed swift supported on the frame for limitedvertical movement relative to the block, a vertically disposed hydrauliccylinder supported on the frame, a piston in said cylinder connected tothe swift for vertical movement therewith, a one-way valve connected atits upstream side to said cylinder beneath said piston, a meteringorifice connected in parallel with said one-way valve, a source of fluidunder pressure, a valve connected between said source and thedown-stream side of said oneway valve operable to connect and disconnectsaid oneway valve and source, means to operate said valve to connectsaid source and one-way valve to raise said swift, means to momentarilyreduce the effective flow of fluid from said source and into saidcylinder beneath said piston in response to upward movement of the swiftinto a predetermined position, means to operate said valve to disconnectsaid one-way valve and source in response to upward movement of saidswift into a second predetermined position, a hydraulic pump having acapacity directly proportional to its speed of operation connected tosaid cylinder to draw fluid from beneath said piston, a relief valve inseries with the outlet of said pump having a pressure settingcorresponding to the weight of said piston and the elements verticallymovable therewith, and electrical means responsive to operation of theblock motor to drive said pump at a speed directly related to the speedof rotation of the block.

References Cited in the file of this patent UNITED STATES PATENTS2,320,554 Barrett June 1, 1943 2,404,368 Esch July 23, 1946 2,626,765Biddison Ian. 27, 1953 2,716,482 Schweich Aug. 30, 1955

